NOTICE: Are you seeing the message "No Import Data" when trying to install a MOD?
Sign into the PSN and start UT3. The game will prompt you to update the game to Version 2.0. Once the game has been updated, try to install the MOD again.
Tutorial - Installing UT3 Mods to the PS3 using a Computer:
This tutorial is going to explain to you how to download Unreal Tournament 3 Mods to your Playstation 3 using a Computer. You can't download the UT3 mods directly to your PS3 Hard Disk Drive unless they are listed under "Available to Download" under the PS3 UT3 Mod Browser. You have to save the UT3 mods to a USB Device or Memory Card.
What you need:
Steps 5-8: Now that the MOD has been saved or copied to the USB Device/Memory Card you can CLOSE the Internet Browser and Eject the USB Device/Memory Card. Next plug the USB Device/Memory Card into the PS3 and Start Unreal Tournament 3. Once the game has started, select "Community" on the Main Menu. In the "Community" Menu select "Mod Browser".
FYI: Steps 5 and 6 are not listed since they applied to installing MODS using the PS3 Browser.
Steps 9-12: Now that you are in "Mod Browser" Press the  Square button to "Import Content". When you press Square you will then select the USB Device or Memory Card that you saved your MOD onto by Pressing X. The game will ask you if you want to import the data. Select Yes.
Now the MOD will begin to import, once the Import is Completed Press O Circle to Back out, and the MOD will unpack and install. Now you will see the MOD in the "Installed Content" section.
To add additional MODS to the game, Exit the Game and go to UT3MOD.COM. When you click on the "PS3 Download Link" of your desired MOD, follow the steps again.